|
Flying the Hypert1 Skies The Hyper-X2 recently broke the record for air-breathing jet planes when it traveled at a hypersonic speed of seven times the speed of sound.Thats about 5,000 miles per hour.At this speed，youd get around the worldflying along the equatorin less than 5 hours. For an engine to burn fuel and produce energy，it needs oxygen.A jet engine，like those on passenger airplanes，gets oxygen from the air.A rocket engine typically goes faster but has to carry its own supply of oxygen.A scramjet engine goes as fast as a rocket，but it doesnt have to carry its own oxygen supply.A scramjets special design allows it to obtain oxygen from the air that flows through the engine.And it does so without letting the fast-moving air put out the combustion flames. However，a scramjet engine works properly only at speeds greater than five times the speed of sound.A booster rocket carried the Hyper-X to an altitude of about 100,000 feet for its test flight.The aircrafts record-beating flight lasted just 11 seconds.Although the little planes self-powered flight lasted only 11 seconds，that brief journey on March 27 makes a major milestone on the way to a new breed of very fast airplanes，comments Werner J.A.Dahm of the University of Michigan in Ann Arbor4.In the future，engineers predict，airplanes equipped with scramjet engines could transport cargo quickly and cheaply to the brink of space. Such hypersonic jets could potentially carry passengers anywhere in the world in just a few hours. 练习： A it was the first air-breathing jet plane. C it flew at speeds smaller than five times the speed of sound. 1. What kind of an engine did the Hyper-X use? B A scramjet engine that doesnt carry its own oxygen supply. D A iet engine that uses no oxygen. A It goes slower than a rocket. C It works only at speeds greater than five times the speed of sound. 2. What did Werner J.A.Dahm of the University of Michigan say about the Hyper-X test flight? B It was self-powered，so it lasted only 11 seconds. D It is a major milestone in the journey of making a new type of very fast airplanes, A To make another 11-second hypersonic flight at 10 times the speed of the sound. C To retest the aircraft that is left. 答案与题解： 1． B 第四段讲了三种发动机的氧气喷气式发动机是从空气中汲取氧气，火箭发动机必须自携氧气，而超音速冲压喷气发动机则不必白携氧气，而这正是Hyper-X使用的发动机装置。 2． D 文章的第六段中，密歇根大学的研究人员Werner J．A．Dahm说，Hyper-X的试飞成功只是研制一种新式快速飞机过程中的一个里程碑，而不是新型飞机的诞生。所以，D是正确选择，A是错误选择。B也不是Werner J．A．Dahm想要表达的意思。C是其他下程师而不是Werner J．A．Dahm说的话。 | 
